براغي رأس مقبس 5/16-18 × 8-1/2 بوصة | محرك مقبس سداسي | ملولبة جزئياً | فولاذ سبائكي معالج أسود حراري (10 / العبوة)

The black oxide finish on these 8-1/2" screws held up perfectly during a heavy jig assembly, and the hex socket drive made tightening them in tight spots much easier than I expected. They feel solid and well-made for the price.

Finally got these partially threaded screws for my jig build, and the thermal black oxide finish looks like it'll hold up way better than standard zinc. Threaded smoothly into 5/16 nuts without any binding or galling, pretty rare at this length.

The partial threading on these screws makes alignment so much easier in my assembly fixture, and the black oxide finish looks clean against the steel. I’ve used a few already and the hex socket holds the driver securely without slipping.